Cacti is an open source performance and fault management framework. Prior to version 1.2.31, a User Enumeration vulnerability allows an attacker to identify valid usernames on the Cacti service. When a user attempts to log in, the application returns slightly different error messages depending on whether the provided username exists in the system. When username exists on Cacti, in the response, they see Access Denied! Login failed. When it does not exist on Cacti, they see Access Denied! Login Failed. The only difference between the responses is the capitalization of the letter "f" in the word failed. This issue has been patched in version 1.2.31.